Dental tool.



DENTAL TOOL.

APPLICATION FILED APR.25, I9I6.

Patented Dec. 12,1916.

SAMUEL A.v CROCKER, JR., OF CINCINNATI, OHIO, ASSIGNOR TO THE SAMUEL A. CROCKER COMPANY, OF CINCINNATI, OHIO, A CORPORATION OF OHIO.

DENTAL TOOL.

Specication of Letters Patent.

Patented Dec. 12, 1916.

Application led April 25, 1916. Serial No. 93,541.

To all whom it may concern.'

Be it known that I, SAMUEL A. CRooKER,

vabrading band for dressing rubber or metal plates. In dental tools of the type disclosed in the United States Letters Patent #574,7 63

issued to Flavel A. Rudolph upon J anuary 5, 1897, the objection has been that their use has been confined to lathes having their heads located on but one side of the operator and running invbut one direction, the abrading element carried thereby having a tendency to loosen upon the arbor of the tool and to therefore fail to be revolved against the work held in. engagement therewith. This objection has been overcome in the tool illustrated in the drawings and described in the following specification. l

An object of my invention is to produce'a dental tool in which means are employed for tightening and for maintaining the abrad-` ing band in position on the expansible mem ber of the tool and which may be used upon either side of the lathe head. This'and other objects are attained in the dental tool described in the following specification and illustrated in the accompanying drawings, in which:

Figure lis a side elevation'of a tool embodying my invention, mounted upon the spindle of a dental lathe head. Fig. 2: is a side elevation of the tool shown in Fig. 1, but showing a portion thereof in section to more fully disclose its construction'. Fig. 3

proved tool upon an enlarged scale.'

My improved construction consists of a socket 4 having a suitable opening 5, for the reception of the lathe head spindle, and an extension 6 provided exteriorly with screw threads as shown in Figs. 2 and 3, adapted to coperate with screw threads formed in the collar-like extension 7 of a nut 8. Located in the extension 6 of the socket 4 and secured therein by means of screw threads 9, is a spindle 10 which at its outer or forward `end is provided with a head 11 preferably screwed onto the end of the spindle or arbor as shown in Fig. 3. Mounted on the spindle 10 and adapted to reciprocate thereon is a sleeve 12, the end adjacent to the screw threaded extension 6 i of the socket 4, being provided with screw threads adapted to vcoperate with screw threads formed within an extension 13 of' the nut 8. Between the extensions 7 and 13 of the nut 8 is formed a knurled portion 14, see Fig. 1, which is provided for the purpose of rotating nut 8. As shown in Fig. 2 the screw threads of the sleeve 12 and extension 6 are so formed that one is right handed and the other is left handed,lor vice versa, as are also the screw threads formed in the extensions 7 and 13 of the nut 8, and which `coperate with. .the screw threads of the By means of this con socket and sleeve. struction the nut 8 may beirotated in one direction and affords rapid movement of the sleeve 12 toward the head 11 because of the double motionproduced thereby, the nut 8 moving away from the socket 4 simultaneously with `the movement of the sleeveI 12 away from the nut 8. On the opposite end of the sleeve 12a flange 15 is formed, the flange being ofsubstantially the4 same size ,as the head 11 and coperating therewith to' retain the member 16 in position on the spindle. The member 16 is preferably made of some suitable yielding material such as rubber so as to permit of its being compressed axially when the sleeve 12 is moved toward the head 11. The purpose of this expansible member is to receive,l a band 17 of abrading material such as emery cloth, 4upon its periphery so that when the flange` 15 is moved bv the sleeve 12 toward the head `11 the cylindrical yielding member;l 16 will be" expanded within the band 17' and thus hold the band 17 securely in position on the is a longitudinal sectional view of my imexpansible member. T order to facilitate the expansible action of the flange 15 and head 11 I have preferably formed their compressing surfaces in a cone-like formation, the object being to increase the tendency for the yielding material of vthe member 16 to be forced outwardlv and to consequently expand within the band 17.

As previously set forth the constructions of dental tools of the type herein disclosed, have been such that they could be used upon only one end ofthe spindle of a lathe head and could be used only when the spindle ber.

balanced by thevoperation of the other so. that the compression of the yielding memwas rotated in one: direction. Upon reversing the rotation of the spindle it has been found that the sleeve would be moved away from the yielding member 16 and thus permit the member to contract 4with the result that the abrading band upon its periphery would become loosened. This is lbecause of the tendency during rotation for thepull upon the abrading band through the yielding member and its friction against the flange of the sleeve, to cause the screw threads of the sleeve to rotate within the -screw threads ofthe nut in a direction such -that the sleeve would be moved away from the yielding member and consequently permit it to become loosened. This prevented the use of a tool of this description upon either end of the lathe head spindle or upon the same end of the spindle when the spindle was subjected to occasional reverse' rtation. This objection has been overcome in my improved construction for the reason that the right and left hand screw threads operate in such a manner that when the tendency is for one screw thread to move in a direction to loosen the yielding member, the other screw thread willmove in the 'opposite direction to tighten the yielding mem- Thus the tendency of one is counterber is `not reduced. This operation of the screw threads occurs upon rotation of the tool 1n either direction, each screw thread opposing the action of the other screw thread whenever thedirectlon of rotatlon is reversed. It will thus be seen that I have y provided a construction in which the tool may be used upon either end of a lathe having screw threads formed at its end, -a

spindle extending therefrom and having a headed end, a sleeve reciprocally mounted on the spindle and having one end screw threaded andl the .opposite end flanged, a yieldingmember located between the head and the flange, and a screw threadedmember cooperating with the screw threads of the sleeve and socket and adapted to force the flange toward the head to expand the 'yielding member, said screw threads being so formed thatuse of the tool during rotation in either direction will maintain uniform expansion thereof.

In testimony whereof, I have hereunto subscribed my name this 24th day of April, 1916. I

SAMUEL A. CROCKER, JR.

Witnesses:

-WALTER F. MURRAY,

W. THORNTON BOGERT.

described my invention, 

